Background

Converting energy efficiently is one of the main issue tackled by the scientific and technological communities. In the last years, more efficient, environmentally acceptable energy transformation equipment suitable at different power output ranges is highly needed in view of modern trend towards a better utilization of fossil fuels and renewable energy and recovering of waste heat in industry and dwellings.

 

The need of an improvement of efficiency of energy conversion systems and simultaneous reduction of emissions stimulate the development of non-conventional heat engines. A demand in better engines is especially evident in the power range from a few kW to a few MW and operated from various heat sources including low grade ones, such as sustainable sources – solar, geothermal energy, biomass, and waste heat.

 

Moreover, it is a matter of fact that a widespread use of micro and mini distributed power generation and cogeneration is delayed now by a lack of suitable prime movers (heat engines). The great majority of power in the range up to several MW is generated today by internal combustion (IC) engines since they are the cheapest and most efficient prime movers in this power range.

 

However they cannot use various available heat sources directly – they consume only more and more expensive hydrocarbon fuels such as gasoline and diesel. Moreover, they are noisy and have the highest emissions among all types of prime movers and the shortest life time and maintenance requirements.